No problem; I find this fun. There's two kinds of gradients: the normal ones, and meshes.

Gradient tutorial time!

First, draw a shape. I made something kind of like an apple.


Select your apple with the normal selection tool thing, and click on pretty much anything in that gradient window to the right, and your apple will start to look like whatever the last gradient you used was.


Fix up the gradient to be how you like. You can drag colors down from the swatches window, select a color on the bar and then modify it using the color tab, or even copy colors by holding down Alt and dragging them. Also, you can change it from being linear or radial. Here I've concocted a pretty appley gradient:


THEN the gradient tool comes in. With the apple still selected, drag the tool across it. This will decide the direction or size of the gradient. I gave it a bit better positioning:


The other kind of gradient is meshes. They are pretty sloppy on hand-drawn shapes, but can do amazing things with primitives. To use one, pick the Mesh tool and click somewhere in the middle of your shape. This creates a node in the middle and some points along the corners. Also note that it makes the outline go away for some reason.


From there you can use the point selection tool to select individual points on the apple and change their color. It will make a gradient between them.


Hope that answers.